Next to Minimal Flavor Violation

TL;DR

The paper explores the Next to Minimal Flavor Violation (NMFV) framework, where new physics couples mainly to third-generation quarks, allowing sizable flavor violation effects at TeV scales while evading current experimental bounds.

Contribution

It introduces the NMFV framework, showing it accommodates sizable new physics contributions to flavor processes without conflicting with existing constraints.

Findings

NMFV models allow ~40% new physics contributions to Delta F=2 processes.

B-factories only beginning to constrain NMFV models.

Correlating Delta F=2 and Delta F=1 processes is effective for probing NMFV.

Abstract

The flavor structure of a wide class of models, denoted as next to minimal flavor violation (NMFV), is considered. In the NMFV framework, new physics (NP), which is required for stabilization of the electroweak symmetry breaking (EWSB) scale, naturally couples (dominantly) to the third generation quarks and is quasi-aligned with the Yukawa matrices. Consequently, new sources of flavor and CP violation are present in the theory, mediated by a low scale of few TeV. However, in spite of the low flavor scale, the most severe bounds on the scale of NP are evaded since these are related to flavor violation in the first two generations. Instead, one typically finds that the NP contributions are comparable in size to SM loop processes. We argue that, in spite of the successful SM unitary triangle fit and contrary to the common lore, such a sizable contribution to Delta F=2 processes of ~ 40% (with arbitrary phase) compared to SM is presently allowed since B-factories are only beginning to constrain these models. Thus, it is very interesting that in the NMFV models one is not forced to separate the scale of NP related to EWSB and the scale of flavor violation. We show briefly that this simple setup includes a wide class of supersymmetric and non-supersymmetric models all of which solve the hierarchy problem. We further discuss tests related to Delta F=1 processes, in particular the ones related to b -> s transition. The b -> s processes are computed using two different hadronic models to estimate the uncertainties involved. In addition, we derive constraints on the NP from B -> Kpi data using only SU(3) flavor symmetry and minimal dynamical assumptions. Finally we argue that in many cases correlating Delta F=2 and Delta F=1 processes is a powerful tool to probe our framework.